Soldering tool



M- J. ROS

SOLDERING TOOL July 26, 949.

Sept 5;

' E attorneys Patented July 26, 1949 SOLDERING TOOL Martin James Rose, Alameda, Calif., assignor to Alan C. Davis, East Haddam, Conn.

Application September 3, 1947, Serial No. 771,896

This invention relates to an electrical tool which may be used to generate heat to raise the temperature of any electrically-conducting material, as necessary for soldering, welding, brazing, drawing or annealing of such material. It has for an object to provide an improved tool of this character which may have a pair of electrodes to engage and clamp the work, and in which either one or both are movable'toward each other to firmly clamp the work between the currentcarrying electrodes during the entire operation, regardless of whether the current is actually flowing through the electrodes.

Another object is to provide a construction including means for protecting the current-carrying-electrodes against over-stressing of the electrode material regardless of the pressure applied to the electrode operating means.

Another object is to provide a construction in which the electrodes are automatically returned to and retained in the open or separated position when the tool is not in use.

A further object is to provide a self-contained switch means in this type of device which is controlled by an actuating lever which changes the relative positions of the electrodes and applies the electrode clamping pressure.

A further object is to provide the combination of a clamping means for holding the work firmly between the electrodes, with a quick-acting selfcontained switch means to control the current for raising the temperature of a piece of electrically conducting material, and which may be used for maintaining that temperature within reasonably accurate limits for a prolonged period, or which may be used for gradually raising or lowering the temperature of such a piece of material, as may be required for certain drawing or annealing operations or for brazing, soldering or Welding together two or more pieces of such material.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within 3 Claims. (Cl. 21926) 2 elements in side elevation, the various elements being shown somewhat diagrammatically and without going into details, to simplify the drawings, and

Fig. 3 is a transverse section substantially on line 3-3 of Fig. 2.

The device shown comprises a pair of electrodes 5 and 6 preferably of carbon or some similar conducting material, or they could be of metal if preferred. These electrodes are electrically insulated from each other except when moved into actual contact with each other orwhen they are in common contact with some electrically conducting material. 'They are also electrically insulated from the supporting structure of the tool and other operating elements, except where necessary for maintaining the electrical current. One of theseelectrodes may be fixed and the other movable, or they may be both movable as found desirable, but to simplify the construction and for ordinary purposes it is preferred to have one of them fixed or stationary, in this case the electrode 5, and the other electrode 6 movable toward and from the fixed electrode 5. In the present structure the electrode 6 is mounted on a conducting lever l pivoted to the housing or supporting structure 8 by any suitable means at 9, so that by operation of this lever electrode 6 may be shifted toward and from the fixed electrode 5 to grip and hold a work piece between them, as will later be described. The fixed electrode 5 may be mounted on a support 10 secured in a recess or slot ll formed in the housing or supporting structure 8, by any suitable means such as the screw 12, which may also be used as a binding screw for connecting an electrical conductor to the support ID, the support I0 being of electrical conducting material. It is also preferred that the electrodes themselves be detachably supported on their respective supports so that they may be readily removed for renewal or repair. In the present case they are shown as mounted by suitable screws l3 with a tongue I4 oneach electrode seated in a fork l5 in their supports,-but any other suitable mountproximately square or rectangular in cross section with the abutting or opposed clamping surfaces substantially fiat and approximately parallel with respect to each other when the electrodes are in the closed position, and with the ends tapered to a more 01" less blunt point. However, it should be understood that the exact form or shape of these electrodes may be varied as required for different uses of this tool. It Will be seen from the drawing that the movement of the electrodes with respect to each other in the form shown is generally similar to the relative move- 'ment of the jaws of a pair of tongs or pliers.

It has beenfhundiiriore CDDVEHiBDiLfiOHIalHUfEC- ture the lverT of metal and use it asa conductor for carrying current to the electrode 6, but it will be understood the device is not limited to this structure, as the lever may be made or some suit able nonconducting material, in WhlCh case it would carry a conductor connected iwith title-else In the drawing a conductor IB 1s* con Tl'ie movabfaeontact is-operatediby an actuateing lver w' pi vot'ed ihti ie supporting structure; orh'ousihg ti' 'by any suitabl'e means; such, for ex? ample, as tlie-cormecting transverse-bolt; This: lever is preferahly of non-eiectricall' yconducting materfmlysueh;forexampldassomemolded plas tie, and such-construction elimih'ates the neces SityfOF providiiig electricail-insulation between this lever and -tlieswitch contaet zll and the eiectrode carrying lever 1';- butwilF: of eourse be -under stood tlie maybe mazde -of other suitable I materials; if it is cram-electrically'condiict ing=-materia-l'-suitable-irisulation-nmst be proviiied when required Movements of -the love:- are-- limited by asuitablestopmeans suchi forexampley asa pinifi mounted in the housing? and p ing throug-h-a curved 'slbt' or other suitable opening w in the 'leverz stop pirr-cooperating the ends of the siot 'or of -the opening 'to limit movements 'oFthe Y lever" opposite direc tiOH'S;

A return sprihg- Z-T' i's ii-it'erposerr between the electrode carrying lever r the supporting structure er housing 8-, and there ism-actuating spriii'rg wbetween the hoxrd lver zfiandi-tlie lever" I. The-spring ZFi's designed-tobeof less strerietl r or have-less thrust that" ofthe' actuating spring ifl, so that the-' spring ZVwill yield-under operating thrust from-thesprhig 2B": The spring 2 his to return thelever' P 'and-theoperatinglever "to-their normal or'inoperativepositionshown;

when maimed-pressure on thelever n is released.

This action ofitliesprihgi! serves a double pur= poses the firstbeihg to mairrtain the 'movable elec trode din theopen position-ready'forthe next'operatibn whenthe tooPisnot beingused; The-se'c- 0nd purpose of this spring is" to disengage the actuating levw'ifl fiom the-switclr 20 when the pressure on this lever is" released: so that the switch is always-"in ites open position when-thetooli is -not use; thus insurii-ig that un=Iessthe tooP is actually i'n use the' circuit to tlie electrodes is open;

'l 'lie m-anually operable lever fl is mounted so" asr to proziect through a: suitabl'e slot oar-opening 2winthe top-orthesupporting stmctur orhous= 75- 4. ing 8 and is so shaped that its upper edge portion projects above the top surface of the housing 8 where it is readily available for pressure of the hand of the operator While gripping this housing. This housing or supporting structure provides a rigid mounting for all the parts of the device and maintains each part in its proper relation to the other parts. In the form shown it is made of non-electricallyT-conducting molded plastic materiat of generally oval shape to fit the hand, and is in two sections 30 and 3| to facilitate manufacture and also mounting of the various elements lever la-which: swings about its ot theedevice, each section being provided with a cavity so that when the parts are connected they -5 fornr a conrpartment tz in which the various elements-- are mounted and Where they are enclosed so. .as.to blethoroughlyprotected. The making of these sections of plastic insulating material simpliiies' the problem of electrical insulation, as

1 various electrical parts may be mounted directly onrthisstnucture;. but it: will: heunderstood. the

housingsmay be-madee of othermateria'lsif found; desirabiegandiiizitiszmade ofimetalzorothenel'ec' trically-e conducting; material; then suitablezinsulation must-1 bes providedsforethe Various eigetpigam conducting; elements: or current-carrying: parts:. The sectionseail a-nd3;|: may befsecmze'd togethenby any: suitable. means, such, for: exam is; asthe screws 24 and: the .boltsz:33:: wthe screw 23:*is:also

' HSEdi-ESlEDiVOll support fioirthe actuatingileven 23;

it iszpzzeierablymade-in twozsectionsr with aescrew section 345 threadectzimo thetappedrendiofthe body section 35, or othersuitazbleetypeofsecurih'g: meanszmay bemsed as fmmdzdesirable'e' The: operation is: as: follows:

it is assumed, fon'example th'at two pieces oi copper: wire'aret-toabes soldered together; they will be placed in contact betweem the} electrodes; hand: 6;

then applies manual pressure tolever: 23: pressurm is transmitted" through thewactuafling-rjsprihg' 28th) theeelectrodecarrying ingrthezspring: 21: a'ssth-i's: isradighter'spring ofl'ess thrust than the spring 28 ;andishiftsithe electrode 6 towardzther eiectrodevfi: and t1ie=-two pieces of wires As; the pressure-on the zleverfl -isiurther inrnzeased tlieelectrode fi firn rly' clarnitlsand holds tbeseswii esibetween-the two electrodesandmain tains thesei'wiresr in contact witfr-each other and in; contact-W1 both electrodes: The-parts are" so designedi amt'arranged that although' the-elem I. trodes E and- 6 are now in electrical contact throughthacopper wiies; the-switch contacts l'9i 2B. *ame still in file-open or'separated "position'and" no current flow through" these electrodes" at" this time; thesefirst movements being to-properly grip-the: elements" to be operated upon; and also to. estabi'isl'rproperoontactbetween them" and'the electrodes 5 and 6 beiore any" current fi'ows. If now th'e operartor still iurther increases the pros sure on tliie aetuating'lever 23*this lever will be furtherdepmessedf but as-the two wires; or theworlsto be operated-upon; arenow firmly clamped between theel'ectrode's hand ii -further movement" of the secondary or electrode-leverT-isthereIiy' prevented. Therefore, on further movement of the-actuating lever 23 the'a'ctuating spring 28"'is compressed; permitting-further-movement" Offth lever" 2'3? and springifi i's so designed that when it is irrcompression it exerts sufficient pressure agaih-st'the Ieve'r'" F- tofirmlyhold the'work'; in this case tlre two copper wires; between electrodes with each other in the space The operator" the actuating pivot-'9 compress 5 and B, but the thrust of the spring 28 is not great enough at any point in the movement of the lever 23 to cause overstressing of the electrode material. This is a very important feature of this invention, as it permits necessary movement of the actuating lever 23, but at the same time controls or limits the clamping force or pressure of the electrodes, preventing any possibility of breaking or injuring these electrodes or the work held by them, and particularly as it permits the use of carbon for these electrodes, which is one of the materials most suitable for such elements, but is of relatively low tensile strength and therefore liable to fracture if overstressed. It also prevents the placing of too great pressure on the articles being operated upon, and provides substantially uniform pressure of the electrodes throughout the entire heating operation which will now take place after the work pieces are properl positioned and clamped, when the pressure on the lever 23 is still further increased.

This further pressure shifts the lever 23 still further in the clockwise direction, or inwardly about its pivot, until it engages the control switch or the operating means for this switch. In the arrangement shown it engages the movable contact of this switch and shifts it into engagement with the stationary contact IS, the spring support 2| yielding for this operation. This closes the electrical circuit to the electrodes 5 and 6, permitting current to flow between the electrodes, the high current flow in this low resistance circuit causing the temperature of the work members (in the example taken, the copper wires) to rise rapidly to a point at which solder will flow readily when placed in contact with these heated wires. In using shop models of this tool, it has been found that when one or more pieces of metal are held firmly between the-electrodes, as described, the metal is brought to proper soldering temperature almost instantaneously when the switch is closed.

Experiments which have been conducted indicate that excessive clamping pressure of the electrodes retards heating of the work to some extent, due to the fact that the contact resistance between the electrodes and the work is thereby reduced. The novel construction and arrangement of this tool possesses an added advantage in that the clamping pressure of the electrodes is a function of the characteristics of the actuating spring 28, which may therefore be designed to provide the electrode clamping pressure which is determined to be the optimum for most eflicient operation.

Although an elongated slot 26 in actuating lever 23 with a pin 25 has been shown as the limiting means for the lever 23, it will be understood the device is not limited to this specific construction, but that other suitable stop means may be employed. Although a lever overtravel stop means is not absolutely essential to the operation of this tool, it is a highly desirable feature in that it protects the switch operating mechanism against possible damage as a result of overpressure or overmovement of the actuating lever 23. It also prevents excessive movement of the electrode lever I under the thrust of the actuating spring 28 and the return spring 21.

To interrupt the flow of current through the electrodes after the temperature of the copper wires has been raised to a point at which the solder will readily flow, it is only necessary for the operator to decrease slightly the manual pressure on the actuating lever 23. A slight decrease in this manual pressure permits this lever to retract or move upwardly under the thrust of the actuating sprin 28. A slight counterclockwise or upward movement of this lever disengages it from the operating mechanism of the switch, or in this case the contact member 20, permitting the contacts to separate under action of the spring 2| and thus interrupt the flow of current through the electrodes. At this point the thrust of the actuating spring 28 against the electrode lever 1 is still suflicient to maintain the electrodes 5 and ii in the clamping position. Thus the work, or in this case the two copper wires, are held firmly in position after the switch I9, 20 has been opened. This provides means for holding the work firmly while the solder is cooling after the current flow has been interrupted, and is a particularly important feature of this tool.

Further, while the work. is held firmly between the electrodes 5 and 6, the control switch may be operated intermittently by slight changes in the manual pressure applied to the actuating lever 23, thus controllin the temperature of the work. This heat control may be used either to maintain an even temperature over prolonged periods or to gradually increase or decrease the temperature of the work, as is required in certain drawing and annealing operations.

Briefly, it will be seen from the above that this tool possesses a number of outstanding advantages over other tools available for similar use. Among the novel and advantageous features the following are believed to be particularly important:

(a) It provides means for holding the work firmly clamped between the current-carrying electrodes during the entire operation, regardless of whether or not current is actually flowing though the electrodes.

(19) It provides means for protecting the current-carrying electrodes against overstressing of the electrode material should excessive pressure be applied to the actuating lever.

(c) The current-carrying electrodes are automatically maintained in the open or ready position when the device is not in use.

(d) It includes a self-contained switch control means which is actuated by the same lever which changes the relative positions of the electrodes and applies the electrode clamping pressure. This eliminates the necessity for providing some external means for controlling the flow of current to the electrodes, and places the entire control of the device in a single manually operable actuating and control lever.

(e) The combination of clamping means for holding the work firmly between the electrodes,

and a quick actuating and self-contained switch means for controlling the raising of the temperature of a piece of electrically-conducting material, provides means by which the operator when desired may readily maintain that temperature within reasonably accurate limits for a prolonged period, or it may be used for gradually raising or lowering the temperature of a piece of such material, as is required in certain drawing or annealing operations, or for brazing, soldering or welding together two or more pieces of such electrically-conducting material.

All of these features make for greater convenience, safety and efficiency, and for more accurate heat control at low-er cost.

Having thus set forth the nature of my invention, I claim:

1. An electric soldering tool of the character c ance 7 described momprising zanrpblong housing in the. form or :a hand grip and sformedofelectrica ly nonconducting material, :a pair of work. clamping electrodesmounted sin-said housing :andprojecting fromene-end ,thereofratleast one of said electrodes being pivoted so :as to :be movable ,toward and from the other ;to clamp and release Work to be heated, electrical supply connections to said electrodes, said housing beingj ovided with a longitudinal-side opening, manually op rablemeans ,for. shifting. the movable electrode toward the other to clampithe'work between them comprising a hand lever of electrically :nonconducting,material pivoted in the housing and; proiecting at one :edge through said opening, an actuatin spring between-the lever and: the electrode so thatforceoftheoperating leverris transferred to the electrode throughsaidspring, areturn spring-or lessthrust thantheacuating spring tending to shift the movable electrode toeseparate the electrodes, .anda control switchin the supply connections. operated by thehmanually. operable lever arranged to ,close the circuit onl aftertheelectrodesengagethe work.

,2. An electric tool of the ;character described comprisinganoblonghousing gfelectricallynonconducting material forming a hand grip and provided with a longitudinal side opening, .a pair of electrodes mounted in .and projectin fr m one end of y-thehousing, .a ,leverin the housin mountin oneof the electrodes -.for.movement toward and from ,the :other to clamp and release work to he heated, electrical s ppl connections to the electrodes, an operating hand lever of electrical nonconductingmaterial pivotally mounted in the housing and projecting atone edge from one 'sidesthereof through saidopening for manual operation, aspring between thesecond lever and the first to transfer pressure irom th uperating lever to the first lever ,to .eiamp the work betweenthe electrodes, areturn sprin of less thrust than the first spring between theother side of the first leverand the housin tending to swing the firstlever in the ,.opposite..direction to releasethe worl, ,..a cont1'ol switch in thehousing to control current to v.the electrodes, and .means ope ated byith enerat ng verfor closineathe switch andso spaced fromsaid lever as tobe operated only after the electrodes have been clamped: on the work.

3.,An electric tool of the character described comprising a substantiallyoval shaped housing of electrically nonconducting material to fit in thewhand-and form ahandgrip and providedwith ano'olong longitudinal opening in one side,;a;pair of electrodes .inthe form of Work clamping jaws projecting from one end of the housing, a lever pivotally mounted in the housing and providing asupport -for;one of the electrodes, electrical, cur.- rent supply {connections to the electrodes, an operating hand lever of electrically nonconducting materialmounted in the housing and provided with ;a longitudinally curved edge projecting through said opening for manual operation, a coiled compression spring between thelevers for transferring pressure from the operating lever to the firstleverto .clamp the work between the electrodes, a coiled compression spring ofless thrust ,than'thefirst spring on the oppositeside of the first lever tending to shift the first lever i i-the opposite direction to release the Work, a controlswitchin the housing tocontrol the current .to the electrodes, and means operated by the operating ,lever controlling the switch and ,so spaced from said lever as ,to close the switch only after the electrodes havebeen clamped on the work.

MARTIN JAM S ROSE- "REFERENCES CITED :ilihefollowing referenlces are of record in the file :;of :this patent:

UNITED STATES PATENTS Number .Name Date -,1 ,995l,55!l Wolt nann Mar. 19,1935

' FOREIGN PATENTS Number Country Date 556,835 Great Britain, Oct. 25,1943 313,774 Switzer1and June 3, 1941 

